It has a round head, bipedal and the size of a dog. So it wasAcrotholus audeti , the new species of herbivorous dinosaur discovered in Alberta (Canada)and belonging to the family of pachycephalosaurs, a name that means “thick-headed reptile.” As the paleontologist David Evans and his colleagues at the University of Toronto have found out by studying its fossil remains, the reptile lived 85 million years ago, measured approximately 1.8 meters from the tip of the tail to the head and weighed 40 kilograms. It is the largest known dinosaur with a bony skull in North America, and possibly the world, according to scientists in the magazineNature Communications.
NameAcrotholusmeans “high dome”, and refers to his skull, domed above the eyes and composed of a solid bone more than 10 centimeters thick. Scientists suspect thatthe animal used its voluminous head, among other things, to fight with head butts. The epithetdaresis a tribute to rancher Roy Audet of Alberta, on whose land the specimen was discovered in 2008.
Small mammals and reptiles can be very diverse and abundant in modern ecosystems, butsmall dinosaurs, weighing less than 100 kilos, are much less common than large ones in the fossil record. Whether this pattern is a true reflection of prehistoric dinosaur communities or is related to the increased potential for small-boned dinosaurs to be destroyed by carnivores and natural decay remains the subject of debate. The good news is thatthe massive skull domes of pachycephalosaurs are resistant to destruction and much more common than their relatively delicate skeletons, so the researchers suggest that their fossil record could provide valuable information on the diversity of small herbivorous dinosaurs.
